Starting control circuit for engines



May 14, 1946. A. J, sMlTH 2,40,216

STARTING CONTROL CIRCUIT FOR ENGINES Filed Aug.` 14, 1944 @ser farm/vCoA/rm INVENTOR. ffxf//Vf/S//m/ ATTORNEYS Patented May 14, 1946 UNITEDSTATES PATENT OFFICE Pacific Enterprise Products Co., Los Angeles,

Calif., a. partnership Application August 14, 1944, Serial No. 549,374

6 Claims.

This invention relates to a starting control circuit for engines.

Where engines are remotely located from switches controlling the circuitof the starting mechanism of the engine and in situations where appendedclaims, reference is had to the accompanying drawing, wherein:

Figure 1 is a wiring diagram of the starter control circuit embodyingthe present invention,

5 illustrating the circuit in somewhat simplied engines have automaticvstarting devices, the form; and build-up voltage of the charginggenerator of the Fig. 2 is a view illustrating one of the latchenginehas been commonly employed to actuate a. type relays that are employedas part of the relay that will open the starter circuit so that thestarter control circuit embodying the present instarter cannot beoperated while the engine is l vention. running. When the engine stopsand the voltage Referring to the accompanying drawing whereof thecharging generator drops, the starter conin similar reference charactersdesignate similar trol circuit is again closed to be ready for asubparts throughout, the present invention relates sequent operationupon the closing of the starter to the starter control circuit of aninternal comcontrol switch. l5 bustion engine, not shown, which may havean A serious objection to the conventional conelectrically operatedstarter indicated at Ill, a trol of the starter circuit by the build-upvoltage charging generator I I, a magneto l2, en ignition of thecharging generator resides in the fact that coil I3, a battery I4, andan ammeter I5. The a failure of the generator, allowing its voltageStarter may have itS control circuit energized by to drop, allows thestarter control circuit to again the closing of a manual or automaticswitch I5 be restored so that on closing the starter switch Which may beremotely located from the engine. the starter may operate even thoughthe engine A similar switch indicated at Il which also may is stillrunning despite the generator failure. If be remotely located iSintended to effect e Shutthe starter is thus caused to operate while theting Off 0f the engineengine is running there is danger of causing seri-In carrying ont the DleScnt invention one Side ous damage to the starterdrive and the ily wheel of Switch l5 may lbe grounded aS indicated atI8, of the engine. and the other side of this switch is connected Anobject of the present invention is to provide through a sot coil I9 of alatch-typo relay through an improved starting control circuit fororigines the ammeter I5 to the ungroundod Side of battery that areremotely operated or which have auto- |4- The other Side of the batteryiS grounded as matic starting mechanisms wherein the starter indicatedat 20. The set coil I9 serves to attract control circuit is opened bythe starting of the en armature 2l against the action of itS Springengine and remains open regardless of the failure 22- This armatureCarries ContactS 23 and 24 of the generator. In this way if thegenerator In the normal position of the armature 2| conshould fail, suchas for example by its belt breaktact 23 engages Contact 25 which is inthe circuit ing, the starter control circuit will still be latchedconnecting magneto l2 to ground 20 Contact in open position so that itis impossible to operate 23 is normally spaced from contact 26 which isin the starter until after the engine has been delibcircuit With aContact 2l thatv is normally elecerately stopped veither by a manual orautomatic tricolly connected by its engagement With concontrol. tact 28with the starter solenoid switch 2e. The Another object of the inventionis to provide an Contact 24 iS normally out of engagement With improvedstarting control circuit for engines Contact 3i! which, in turn, iselectrically conwherein latch-type relays are used in the starter nectedt0 one side of each of two trip Coils 3i and control circuit and in themagneto and/or igni- 32- Contact 24 iS connected tlc-rough aminetel tioncircuits which serve to latch open the starter l5 to the ungrollndcdSide of battery le and concontrol circuit when the engine has beenstarted tact 23 which is connected to ground 20 will to latch open themagneto ground wire to latch ground contacts 25 or 26, depending onwhich of closed the ignition circuit and to latch closed trip thesecontacts it engages. coils associated with the latch-type relays thatAdjacent the armature 2l there iS e Divoted serve to release the latchesof the latch-type relay latch 33 actuated by a Spring 34 into latohingwhen manual or automatic conti-o1 switches are position to hold thearmature in the position'to closed. which it may have been moved by theattraction With the foregoing and other objects in view of the set coil19. which will be manifest in the following detailed The 'startercircuit includes ground 34, the

description and `specii'lcally vpointed out "in the solenoid Aswitch 29,and "battery I4. The coil of the solenoid switch is connected to contact23 which is normally engaged by contact 21 of the starter cut-out relaywhich has a set coil 35 and a trip coil 3|. The starter cut-out relay isalso a latch-type relay similar to that illustrated in Fig. 5 2, exceptthat its armature carries only contact 21. When the set coil 35 isenergized movement of the armature of this latch-type relay causescontact 21 to disengage contact 28 and to be latched in open positionuntil such time as its trip coil 3| is energized which attracts itslatch corresponding to latch 33 and allows contact 21 to reengagecontact 28 and thus again close the circuit from contact 2B through thecoil of the starter solenoid switch. The set coil 35 has one sideconnected to ground 20 and the other side connected to the armature ofgenerator I I. The generator is connected through a cut-out and voltageregulator to the ammeter I5 and thence to the battery I4.

The operation and advantages of the abovedescribed construction are asfollows: Assuming that the engine is stopped, on closing switch IB setcoil I9 is energized attracting armature 2| and, causing contact 23 todisengage contact 25 which opens the ground on the primary of magnetoI2. 2z Simultaneously contact 23 will engage contact 26 which closes thecircuit through contacts 21 and 28 to the starter solenoid switch 29.When the starter solenoid switch is thus actuated battery I4 isconnected through the starter I0 to ground 34 and the starter operatesto start the engine. Acuation of armature 2| also causes contact 24 toengage contact 30, thus closing the circuit to the ignition coil I3. Itwill be understood that the engine may either have battery ignition ormagneto ignition or as frequently occurs, the same engine may beequipped with both magneto and battery ignition.

When the engine starts, generator builds up voltage and when thisvoltage is suilicient to correspond to normal ruiming conditions itcauses the set coil 35 of the starter cut-out relay to be energized.This attracts its armature causing contact 21 to disengage contact 28.The armature of the starter cut-out relay is latched in this attractedposition and remains so latched until trip coil 3| is energized.` Inthis manner after the engine 'has started, the starter control circuitwhich includes the starter solenoid switch 29 is opened and held openuntil trip coil 3| is energized. Consequently, if generator should failfor any reason, such as for example by its belt breaking, set coil 35may no longer be energized but as its armature is held in latchedposition, contacts 21 and 28 are held open. Consequently, even if switchI6 should again be closed, the starter control circuit which includesstarter solenoid switch 29 can not be closed due to contacts 21 and 28still being open. y In this manner, it is impossible to actuate thestarter |I while the engine is running even though the generator mayhave failed. In order to re-establish the starting control circuit it isnecessary to either deliberately or automatically energize trip coil 3|.Thus, if switch I1 is closed, this' causes trip coils 3| and 32 to bothbe energized to actuate their respective latches and release theirrespective armatures. When the trip coil 32 is energized and armature 2|is released, thel magneto is grounded by contact 23 engaging contact 25.The ignition coil circuit is opened by contact 24 disengaging contact 30and the trip coil circuits are themselves opened by the opening of thesesame contacts 24 and 30. Contact 23 on disengaging contact 26 also opensthe starter control circuit, preventing operation of the starter withthe ignition relay in the trip position, even though contacts 21 and 28may be closed. Energizing of trip coil 3| enables contact 21 to reengagecontact 28, thus making the starter control circuit ready for operationagain by re-closure of the ignition relay or closing switch I6. With theengine having thus been shut down by the closing of switch I1, thestarter control circuit is thus restored and the starter may then beoperated by closing switch IB.

In lieu of or in addition to employing the generator II to energize setcoil 35 a centrifugal switch 3|) may be connected between the ammeter I5and one side of the set coil of the starter cutout relay. Thiscentrifugal switch is designed to close when the engine has been broughtup to a predetermined speed. When it closes it, of course, energizes theset coil 35 opening contacts 21 and 28, thus opening the starter controlcircuit as previously described.

In the event of failure of the centrifugal switch while operating sothat set coil 35 is no longer energized, contacts 21 and 28 do notimmediately close but are held open until trip coil 3| is energized,such as by closing of switch |1.

The engine may have various automatic control devices indicated at 4|,42 and 43. For example, 4| may be an oil cutout operating upon a seriousdrop in lubricating oil pressure, 42 a high water temperature cutout and43 an overspeed cutout. Other automatic controls may be employed ifdesired to automatically energize trip coils 3| and 32 in the event ofvarious contingencies. The details of these various cutouts are notillustrated other than to indicate that in the event of their respectivecontingencies they close the circuit through the trip coils to ground.Thus in the event that the oil pressure of the engine is loW or thelevel of oil in the crankcase is low, or the temperature of the enginecooling water becomes excessively high or the engine speed rises above apredetermined value, these cutouts may serve to actuate the trip coils3| and 32 to automatically stop the engine. Their effect upon the tripcoils and upon the starter control circuit is the same as if switch I1were closed. thus shutting down the engine. If one of thecutouts 4I, 42or 43 are closed, to shut down the engine, the engine may thereafter bemomentarily started on closing switch I6, but as soon as this switch isopened, these cutouts will immediately energize the trip coils 3| and 32to again shut the engine down.

While switch I6 is illustrated as being a manually operated remoteswitch, it will be appreciated that this switch may be an automaticcycling switch such as that illustrated in the copending application ofJohn H. Wallace,.Serial No. 488,199, filed May 24, 1943, or it may beany other automatic switchdesigned to start the engine at predeterminedtimes. In the event that the engine protective cutouts such as 4|, 42 or43 are not employed for engine protection and the engine stops withoutswitch I1 having been closed, such as for example by the exhaustion offuelr in the fuel supply, then in order to restart the engine it isnecessary to rst close said switch I1 which closes the circuit to thetrip coils of both relays.

From the above-described construction it will be appreciated that animproved starter control circuit is provided which protects the engineagainst operation of the starter by switch I5, even in the event thatthe generator II or centrifugal switch 40 should fail While the engineis running. By the improved construction it is iml possible to operatethe starter l unless the engine has been deliberately or automaticallyshut down by the closing of switch l1 or the equivalent thereofoccasioned by operation of the cutouts 4 I, 42 or 43. Consequentlydanger of damage to the starter mechanism is largely eliminated inasmuchas the starter mechanism cannot ordinarily be operated while the engineis running.

Various changes may be made in the details of construction withoutdeparting from the spirit and scope of the invention as defined by theappended claims.

I claim:

l. In combination with an engine having an electrically operatedstarter, a set coil adapted to be energized upon the starting of theengine, a pair of contacts in circuit with the starter normally urgedinto engagement so as to ready the starter circuit but adapted to beopened when the set coil is energized to render the starter circuitinoperative, means for latching said contacts out of engagement when theset coil has been energized, and a trip coil adapted when energized tocause said latch means to release the contacts for reengagement, andmeans for energizing the trip coil.

2. In combination with an engine having an electrically operatedstarter, a set coil adapted to be energized upon the starting of theengine, a pair of contacts in circuit with the starter normally urgedinto engagement so as to ready the starter circuit but adapted to beopened when the set coil is energized to render the starter circuitinoperative, means for mechanically latching said contacts out ofengagement when the set coil has been energized, and a trip coil adaptedwhen energized to cause said latch means to release the contacts forreengagement, and means for energizing the trip coil.

3. In combination with an engine having an electrically operatedstarter, a set coil adapted to be energized upon the starting of theengine, a pair of contacts normally urged into engagement to ready thestarter circuit but'adapted to be opened when the set coil is energizedto render the starter circuit inoperative, means for mechanicallyholding said contacts open after having been opened by the set coil, anda4 relay having contacts arranged to close the starter circuit throughthe mentioned contacts and to close the ignition circuit of the engine.

4. In combination with an engine having an electrically operatedstarter, a set coil adapted to be energized upon the starting of theengine, a pair of contacts normally urged into engagement to ready thestarter circuit but adapted to be opened when the set coil is energizedto render the starter circuit inoperative, means for mechanicallyholding said contacts open after having been opened by the set coil, andan ignition relay having a set coil and normally open contacts adaptedto be actuated by the set coil to close the starter circuit through therst-mentioned pair of contacts when they are closed and to also closethe ignition circuit of the engine, means for energizing the set coil ofthe ignition relay, means for mechanically latching the contacts of theignition relay in the position they are moved to by the energizing ofthe set coil of the ignition relay, a trip coil for causing said latchmeans to release the contacts of the ignition relay to allow them toopen, and means for energizing the last-mentioned trip coil.

5. In combination with an engine having an electric starter, a startercutout relay having a set coil adapted to be energized when the engineis started and normally closed contacts controlling the starter circuitadapted to be opened when the set coil is energized, means formechanically latching said contacts in open position, a trip coil forcausing the latch means to release, an ignition relay having a set coiladapted to be energized, normally open contacts adapted to be actuatedthereby to close the starter circuit through the first-mentionedcontacts when they are closed, and to close the ignition circuit of theengine, means for mechanically latching the contacts of the ignitionrelay in closed position, an ignition relay trip coil adapted to releasethe latch means of the ignition relay, means for energizing the set coilof the ignition relay, and means for energizing both trip coils.

6. In combination with an internal combustion engine having an electricstarter, a starter cutout relay having normally closed contacts in thestarter circuit, an ignition relay having normally open contacts in thestarter circuit, set coils for both of said relays adapted to open thecontacts of the starter cutout relay and close the contacts of theignition relay, means for energizing the set coil of the starter cutoutrelay when the engine has been started, means for energizing the setcoil of the ignition relay, latch means for latching the contacts ofboth of said relays in the positions assumed when their set coils havebeen energized, trip coil means for releasing the latch means of both ofsaid relays, and means for energizing the trip coil means to allow thecontacts of both relays to return to their normal positions.

ALVIN J. SMITH.

